Lighter construction



June l0, 1,969 L. K. MULHQLLAND T AL 3,448,711

LIGHTER CONSTRUCTION ,4 frag/vf y;

June 10, 1969 K. MULHOLLAND AL. 3,448,711

LIGHTER cNsTRUcTIoN Filed oct. i1, 1967 SN QN June l0, 1969 K. MuLHoLLAND ET AL 3,448,711v

' LIGHTER CONSTRUCTION Filed Oct. 11, 1967 sheet 4 of 5 June 1o, 1969 Filed Oct. ll, 1967 LIGHTER CONSTRUCTION Lawrence K. Mulholland, North Aurora, Ill., and Ammon W. Kersteter and Adolph C. A. Baste, Newark, Del., assignors to Wiley Manufacturing Company, Port Deposit, Md., a corporation of Delaware Filed Oct. 11, 1967, Ser. No. 674,527 Int. Cl. B63b 35/28, 25/02 U.S. Cl. 114-26 16 Claims ABSTRACT F THE DISCLOSURE An improved lighter, or barge, is provided with a novel double wafll construction throughout its entire hull, and the double wall construction includes features which make the lighter stronger, completely buoyant without a loss of cargo space, and more reliable in preventing loss or damage to cargo. Further, the novel construction provides for an assembly of a hull from a number of identical assembly elements, thereby permitting a lighter to be mass produced more efficiently and at a lower cost than with prior assembly requirements. The improved lighter is constructed to be stacked or otherwise stowed aboard a larger ocean-going cargo ship, and the novel double wall construction of the lighter provides for increased cargo capacities for individual lighters and for a number of such lighters that are carried aboard an ocean-going vessel.

Brief summary and background The invention relates to an improved lighter or barge construction. The lighter which is contemplated by the present invention is of a type which may be used to carry cargo back and forth between a port and an oceangoing vessel and which may be stacked or stowed aboard the ocean-going vessel for containing cargo until it reaches its destination.

It is known in the prior art to provide for some type of barge or lighter construction which will permit the lighter to be lifted aboard a large cargo ship. Generally, conventional constructions for barges or lighters have been used for such purposes, and there has been an emphasis in the industry to modify the relatively large cargo ships so as to receive and carry a number of stacked or stowed barges. Improvements which are directed towards modifying or adapting cargo ships to such uses are disclosed in Goldman Patent 3,273,527 and Nemec Patent 3,318,276. However, little has been done to improve the construction of individual barges or lighters which are intended to be carried aboard such cargo vessels, and as a result, individual lighters are relatively costly for such uses and much cargo space is wasted in actual use. Accordingly, the present invention is directed to improvements in construction and assembly techniques for a lighter which may function to carry cargo back and forth between a mother ship and a port, and to be received and carried aboard the ocean-going mother ship. In this sense, the -improved lighter of the present invention functions not only as a barge but also as a stowable container which will safely protect a cargo whether it is being floated on a body of water or being carried within or on the deck of a larger ship.

The conventional lighter which has been in use in systems of the types described in the above mentioned patents comprises a relatively conventional hull construction having a single wall throughout a major part of the hull together with relatively large buoyancy tanks positioned at either or both ends of the hull. The typical, prior art,'hull construction has been made up of a plurality of dissimilar units which are riveted and welded together United States Patent O lCe to form the desired hull shape, and usually, the interior surface of such a construction is interrupted with flanges or ridges at the seam lines where hull elements are joined together. This type of construction has been standard and necessary to provide sufficient strength for a barge which is intended to carry and store a given cargo. However, such prior art constructions have proven to be very costly and otherwise unsatisfactory for use in modern day systems of floating cargo out to a mother ship and storing the same in the mother ship in the same barge which carries the cargo out.

It will be appreciated that relatively large numbers of barges or lighters are required in a working system which contemplates a large inventory of such barges at each sea port which is to service an -incoming or outgoing ocean vessel. While a given vessel is unloading whatever number of cargo carrying lighters it may contain, it is economically des-irable to have an equal number of lighters standing by with new loads for transporting out to the mother ship before it leaves port. An even greater inventory is required if lighters are used for temporary storage of cargo at a sea port until unloading or further handling is convenient. Thus, it is necessary that the large numbers of lighters which are required for such cargo handling systems be economically and efficiently produced without reducing reliability as to safe handling and storage of cargo.

The present invention overcomes the problems of prior lighter constructions by providing a substantially improved hull which is made up of a double wall construction in its entirety. The double wall construction of the present -invention includes inner and ouer walls which are spaced apart from one another and which include a relatively large number of divider plates therebetween so as to provide a great number of separate, sealed compartments throughout the entire hull construction. With the improved double wall construction of the present invention, there is no requirement for providing large, space-consuming reserve buoyancy tanks at either end of a lighter, and a more reliable and safer buoyancy is provided by the large number of compartments provided in the double wall construction of the hull. Another very important feature of the present invention resides in a particular arrangement and assembly of novel hull plate members which make up at least the inner walls of the improved lighter, and both inner and outer walls may be assembled from the novel hull plate members. The hull plate members may be essentially indentical in configuration and are of such a standardized configuration that they can be rapidly produced and assembled in accordance with modern day mass production techniques. The hull plate members include flanges along their marginal edges so that adjoining hull plates can be welded in edge-to-edge relationships, thereby providing an essentially smooth and uninterrupted surface on one side of the wall which is being formed. The inner and outer walls are arranged so that all flanges turn inwardly towards the space contained between the walls, an'd thus, the inner and outer surfaces of the lighter are essentially smooth and uninterrupted. The provision of a smooth inner surface for a lighter represents a substantial improvement inasmuch as bulk cargo can be more easily stowed and removed, and the lighter can be more easily cleaned when it is being used for different types of cargo after each useagc. Prior art constructions have required time consuming cleaning operations to work around all of the seams and flanges necessarily formed in such constructions, and typically, it has been a practice to custombuild a wooden lining or sheathing for most lighters so as to accommodate bulk cargo. Of course, the added weight and cost in providing a wooden lining detracts substantially from the economical and efficient use of a given barge or lighter construction.

The improved lighter construction of the present invention also permits an easier handling and stowing of a number of such lighters in stacked relationships to one another. Lifting means may be provided on all four corners of the lighter so as to receive spanning members which can be inserted between the lifting posts, and the spanning members function to relieve stresses in the lighter hull while it is being lifted into and out of a cargo ship. Also, the lifting posts are constructed to be received by, and mated with similar posts of an adjoining lighter when two or more such lighters are stacked one upon the other. The improved lighter also includes a novel arrangement of a relatively large hatchway through its top, and the hatchway extends all the way across the lighter with no side portions of the lighter overhanging or otherwise interfering with the loading of cargo into the lighter. In its preferred embodiment, the lighter is also provided with its own hatch cover which can be closed to seal the hatchway and to protect the contents of the lighter while it is being transported over a body of water or carried aboard a cargo ship.

These and other advantages of the present invention will become apparent in the more detailed discussion that follows. In the detailed discussion, reference will be made to the accompanying drawings as briefly described below.

Brief description of drawings FIGURE 1 is a top plan view of one form of improved lighter construction of the present invention;

FIGURE 2 is a side elevational view of the lighter shown in FIGURE 1;

FIGURE 3 is a cross sectional elevational View of an end portion of the improved lighter, as taken at line 3-3 of FIGURE 1;

FIGURE 4 is a detailed representation of a reinforced upper end of the improved lighter of FIGURE 1;

FIGURE 5 is a vertical, sectional view of a portion of an overhang construction at an end of the lighter;

FIGURE 6 is a horizontal sectional view taken at line 6-6 of FIGURE 3;

FIGURE 7 is a vertical, sectional end view of the FIG- URE 1 lighter construction, as seen one lines 7-7 of FIGURE 2;

FIGURE 8 is an elevational cross sectional view of a lifting and mooring post construction;

FIGURE 9 is a side elevational view of a portion of an alternative form of lighter construction;

FIGURE 10 is a cross sectional elevational view of an end portion of the alternative lighter construction similar to the view of FIGURE 3;

FIGURE 11 is a detailed view of a reinforced section of the alternative lighter construction, comparable to the FIGURE 4 view of the iirst form of lighter;

FIGURE 12 is a horizontal sectional view, similar to the FIGURE 6 view, of the alternate form of lighter;

FIGURE 13 is a detailed view of the alternate lighter, as is comparable to a portion of the FIGURE 7 view of the rst lighter construction; and

FIGURE 14 is a horizontal sectional view taken on lines 14-14 of FIGURE 10.

Detail description of invention As already discussed, the improved lighter of the present invention is intended to function not only as a cargo carrying barge but also as a container which can be stacked and stowed aboard an ocean-going vessel or at a seaport. Such a lighter construction must provide for sucient strength to carry the cargo and to be lifted completely out of a body of water when being loaded or unloaded relative to a larger cargo ship. Ideally, the lighter should be strengthened for repeated handlings of this type without sacricing buoyancy and other factors of reliability in protecting a cargo which is being hauled or stored. The improved lighter construction of the 4present invention offers all needed advantages of strength and reliability for safe use together with an additional advantage of being easily constructed from standardized assembly units which are efliciently and economically assembled into the finished product.

Referring to FIGURES l and 2, top and side views of the improved lighter are illustrated. The illustrated lighter is of a relatively large capacity, of the type useful in the systems described in the above patents, and a typical capacity of the improved lighter is approximately 20,000 cubic feet. In contrast, prior art barges which are presently in use with the described systems and which have similar outside dimensions carry only about 18,000 cubic feet and can fill a ship to only about fifty percent of its load capacity. The present invention provides for substantially improved capacity of individual lighters, without sacrificing strength or buoyancy, and the lighters of this invention can be stacked within a cargo ship with greater efficiencies in the use of a cargo ships load capacity.

The lighter which is illustrated has generally rectangular side and end walls and a bottom, and all portions of the lighter hull are constructed from a double wall construction which will be discussed in greater detail below. The form of lighter which is shown in FIGURES 1 and 2 may have typical measurements of about a 61 foot 6 inch length, a 31 foot 2 inch width, an overall height of 13 feet, and a hatch opening which is 29 feet `6 inches by 44 feet. Such dimensions are suitable for the cargo handling systems described in the above mentioned patents, and at the same time, the lighter is suiciently strong to withstand the stresses which are encountered in handling such a vessel in and out of the water. However, it is to be understood that other dimensions may also be used, and the ones just given are by Way of example only. Additionally, the overall conguration of the lighter may be somewhat dilferent than that shown in the figures, but the illustrated configuration is especially useful for eicient use of cargo space when a number of such lighters are stacked or stowed in a large ocean-going vessel.

One featuer of the present invention is the provision of a double wall construction for the entire hull of a lighter, and the double wall construction also includes a relatively large number of compartments separated from one another to provide buoyancy. As viewed in FIGURE 3, there is an inner wall 12 and an outer wall 14 for the bottom and end walls of the lighter. Likewise, the side walls are provided with a double wall construction, as shown in FIGUR-ES 6 and 7. The inner and outer walls 12 and 14 are spaced from one another to provide a compartmented air space therebetween throughout the entire hull construction. The inner and outer walls are divided up into a plurality of compartments by divider plate members 16 interconnected between the inner and outer walls. Although the inner and outer walls may be formed in any convenient manner, it is another feature of the present invention that each wall may be formed from a number of standardized hull plate members, and a majority of the hull plates making up a given end, side or bottom wall are of identical dimensions. The hull plate members and divider plate members may be mass pro- -duced out of 1A inch steel plate, or any other suitable material, and then they are assembled to form the lighter construction shown in FIGURES 1-8.

FIGURES 3 through 7 illustrate details of a lighter construction with respect to a use of standardized hull plate members for both inner and outer wall constructions of the lighter hull. Individual hull plate members 18 comprise essentially at, elongate plates with turned marginal edges which form flanges 20. In the construction of a lighter, a series of individual hull plate members 18 are arranged in an edge-to-edge relationship and with divider plates 16 interposed between adjoining flanges of adjacent hull plate members. Then the hull plates and divider plates are welded together with known welding equipment to provide .a welded seam along the edge-toedge contact of adjoining hull plates with an interposed divider plate 16. This assembly procedure can be carried out for an entire end, side or bottom wall of a lighter in one operation, and it is contemplated that automatic welding rigs may be used for welding a number of seams simultaneously. The operation is repeated in the formation of a second wall which is spaced from the first formed wall, and a completed yassembly and welding operation produces the illustrated double wall construction having a plurality of sealed compartments formed by the divider plates 16. Of course, the divider plates 16 extend for the entire length of the hull plate members so as to completely seal adjoining compartments from one another. Although the FIGURES 1-8 illustrate horizontally disposed compartments for the end walls and vertically disposed compartments for side walls of a lighter, it will be understood that the walls can be assembled with the compartments positioned in any desired attitude. Likewise, the bottom of the lighter may be produced with compartments which run lengthwise rather than crosswise of the compartment, as has been illustrated.

The improved double wall construction which has been just described offers a number of advantages. Firstly,

there is less likelihood of the lighter being ruptured to such an extent that cargo will be lost or damaged. In prior constructions having only a single wall throughout a major portion of a hull, there has -been a danger of damage to, or loss of cargo from, a damaged or leaking hull. Secondly, the provision of separate and discrete compartments which are sealed from one another within any given wall construction provides vadditional protection in the event that a portion of a hull is penetrated or damaged. Since the individual compartments collectively provide for buoyancy of the entire lighter, it can be seen that damage to one or several compartments will not result in a substantial loss of buoyancy for the lighter. Furthermore, the divider plates 16 function to seal adjacent compartments from one another, and therefore, a

leakage in one compartment would not affect adjoining compartments. Another related advantage in providing a double wall construction of the type described resides in a capability for repairing a damaged or ruptured outer wall while the lighter is stowed aboard a cargo ship and with out removing the cargo which is contained within the lighter. If a portion of the outer wall of a lighter is penetrated or otherwise damaged in handling, water will not contact the cargo within the lighter, and when the lighter is lifted into a stowed position, water will drain out of the particular compartment area which has been damaged. Thus, a repair maybe effected without removing cargo from the lighter. A third, and important feature of the double wall construction which has been described is in the improved strengthening of a lighter or barge for use in integrated lighter and cargo ship systems. Prior art barge constructions of the single wall type having required substantial reinforcement along the upper side walls of the barge to prevent bulging or over-stressing of the barge side walls when loaded. Typically, the side walls have been strengthened by providing a relatively broad overhanging deck structure along each side of the barge, and a loading hatchway was limited to a position between the overhanging deck portions. Thus, the size of the hatchway opening was necessarily narrower than the interior width of the lighter, and it was necessary to drop ya load downwardly through the hatchway and to then shift the load laterally towards the side and end walls in order to ll up the lighter or barge being used. In contrast, the present invention provides for an improved and stronger construction wherein at hatchway may extend all the way across a lighter from one inner side wall to an opposite inner side wall. With the present invention, it has been found that there is no necessity in providing a reinforcing overhang along the margins of the lighter,

and thus, the lighter can be loaded more rapidly and eff ciently with less time lost in lateral shifting of the load from one place to another in the lighter. FIGURE 7 illustrates the side wall construction .attainable with the principles of the present invention, and it can be seen'l that there is no overhanging deck portion. A coaming 22 is provided at the upper ends of the side walls and across the ends of the hatchway 10` for supporting a hatch cover has been omitted from the drawings for clarity and does not form a part of the invention to be covered by this application, however, the hatch cover may be of a folding and stacking type which can be moved to either or both ends of the lighter to open the hatchway 10. When the hatch cover is to be stacked at the ends of the hatchway, overhanging deck portions 24 (see FIGURES 3 through 5) are provided for supporting the hatch cover panels which are to be stacked. FIGURE 5 illustrates in cross section a type of reinforcing structure which may be used for overchanging deck 24, but alternatively, the deck 24 may be made from a double wall construction of the type already described with reference to the end side and bottom walls.

FIGURE 4 illustrates another constructional detail of importance to the lighter construction when it is to be stacked or stowed aboard a larger ship. The cross sectional end view of FIGURE 4 is taken at a position of a towing bit 26 of the type shown in FIGURE l. The towing bits 26 function to receive lines which can tow one or more of the lighters across a body of water. Beneath the locations of the towing bits, or at any other convenient location, reinforcing plates 28 are provided for reinforcing sections of the upper end walls of the lighter. The purpose in providing reinforcing plates 28 along the end walls is to provide a strengthened section which may receive stresses from a wedge means -used in xing the positions of stacked lighters Within frames in a cargo ship. In addition, corners of the lighter may be protected with bumper members 30 which will prevent any damage to lighters which are being stacked adjacent to one another within a ship.

When the lighter of the present invention is to be used -with a system of the type described in Nemec Patent 3,318,276 it is not necessary that any additional lifting means be attached for lifting the lighter relative to a ship in which it is to be stowed or carried. The Nemec system contemplates the use of an elevator at the end of a ship, and the elevator provides the lifting means necessary for moving a lighter relative to the ship. However, when the lighter is to be lifted by a crane into and out of a ship, as suggested in the Goldman Patent 3,273,527, it is necessary to attach a lifting means to the lighter itself. FIGURES l and 2 illustrate typical lifting posts 32 which may be used with the lighter construction of the present invention. As shown in FIGURE 6, the lifting post structure is integral with the double wall construction provided for the lighter hull, and thus, the lifting post is a very strong part of the entire hull construction. The lifting posts which are shown in FIGURES l, 2 and 8 are of a special configuration to receive spanning bars (of any conventional type which can be inserted and spread between adjacent posts) for interconnecting all four lifting posts 32. Once the spanning bars are in position and rigidly fixed between the four corners of the lighter, cable connections can be made to the bars for lifting the lighter relative to a ship. The use of spanning bars with the corner posts which are illustrated provide for a uniform distribution of stresses around the entire lighter hull so as to prevent any extreme stress or bulging in any particular portion of the hull. 'Ihe corner posts 32 also include con- 'figurations for their upper and lower terminal ends which will mate with one another when one lighter is stacked on top of another. 'Ihe tapered upper end of the corner post 32 is shaped to be received within a mating depression 34 (see FIGURE 3) in the bottom end of an adjoining corner post of another lighter.

An alternate form of lighter construction is shown in FIGURES 9-14. The alternate form of construction also provides for a double wall hull construction throughout the entire lighter body, but the outer walls 14 are constructed in a different manner than was described in the FIGURES l-7 embodiment. As can be seen in the detailed views, the outer hull walls 14 are formed from relatively large sheets of material which cover a large number of individual compartments formed by the inner wall plate members and divider plates associated therewith. Thus, the alternate form offers advantages in more rapid assembly and in having fewer welded joints on the outside Wall which would be possibly subject to fracture or other failure. For an example of construction of the alternate form of lighter, two plates 42 (see FIGURE 9) may form one entire outer wall of a lighter from a forward post 32 to a rearward post 32 (the FIGURE 9 construction being comparable to the general configuration shown in FIG- URE 2). Each of the plates 42 may be seventy-two inches in height, and thus, the two plates form a total height of approximately twelve feet for a lighter. In a similar manner, the bottom outer wall of the lighter may be formed from seventy-two inch width plates which extend transversely across the lighter, and the end walls may be formed in a manner similar to the formation of the side walls.

In assembling the alternate form of lighter of FIG- URES 9-13, the outer plates are aligned in an edge-toedge relationship, and then, the numerous divider plates are xedat right angles to the inner surface of the outer plate assembly so that the divider plates can be welded in place. After the divider plates are welded in their respective positions, the individual plate members 18, which make up the inner walls of the lighter, are placed between the divider plates and welded to their exposed edges. As with the first form of lighter construction, the individual plate members 18 are of a standardized size and shape and have edge flanges which assist in the placement and welding of the individual plate members to the divider plates.

FIGURE 14 illustrates details of a bilge well 44 which may be incorporated in a compartment in the bottom of the hull. As shown also in FIGURE l0, a suction pipe 46 may communicate with the bilge well for emptying the same.

Although the alternate form of construction has been described with reference to a use of relatively large plates on an outer wall construction, it will be appreciated that the inner and outer wall formations may be reversed from what has been described. However, it is preferred to use the relatively large plates on the outer walls to reduce danger of damage on the outside hull. Also, it is to be understood that the relatively large plates which are used may be of different sizes and shapes, than those described by way of example, and the large plates may be arranged in different relationships than what has been described. Any suitable metal plate material may be used for all portions of the novel hull constructions of this invention.

Having described the structural features of the present invention, it can be seen that a substantially improved lighter is provided having special features of strength and buoyancy with additional protection for any cargo which is being carried. The entire lighter may be assembled from standardized metal plates, and the particular compartmented construction which has been described offers increased strengths and load capacities for whatever metal material is used in the construction. The inner wall surfaces of the improved lighter are essentially smooth and uninterrupted, as compared to prior art constructions, and there is no requirement for adding a special sheathing or lining to the lighter of this invention. Although the lighter has been described with particular reference to its utility in a system for stowage on a larger cargo ship, it will be appreciated that the same constructional features are useful for any barge or lighter. The construction of this invention may be used in river lighters or in any other hull construction requiring the advantages of strength and buoyancy which have been discussed.

The invention has been described with particular reference to a preferred embodiment, but it will be appreciated that obvious variations will become apparent to those skilled in this art.

What is claimed is:

1. An improved lighter construction suitable for hauling cargo between a port and a cargo ship and for being stowed or carried aboard the lcargo ship in a stacked relationship to lighters of similar construction, comprismg a hull having a bottom, side walls and end walls, all of which are formed with a double wall construction so as to provide a reliable buoyancy for the lighter Without a requirement for space-consuming reserve buoyancy tanks, said double wall construction also providing for increased strength of the lighter and greater safety for cargo by protecting the cargo 0n all sides from damage resulting from a rupture of either wall making up the double wall construction, said double wall construction of the hull further comprising:

an inner wall and an outer wall, each of which are made up of a plurality of hull plate members connected in edge to edge relationships to form a continuous wall structure, and including divider plate members connected between the edges of said hull plate members and at substantially right `angles thereto so as to form a plurality of sealed compartments between said inner and outer walls, said plurality of compartments being sealed from one another so as to maintain buoyancy of the lighter in the event that a hull plate member of a compartment is ruptured or otherwise damaged, said hull plate members of at least one of said walls having flanges along their edges so that the flanges can be connected to edges of divider plate members which are included between the anges of adjoining hull plate members, said flanges functioning to support said divider plate members while a divider plate member is being welded between an adjoining pair of hull plate members.

2. The improved lighter of claim 1 wherein a majority of said hull plate members and said divider plate members for a given bottom, side or end wall of the lighter are of uniform dimensions, whereby the lighter can be more eiciently fabricated ata lower cost of manufacture.

3. The improved lighter of claim 1 wherein the inner wall of the lighter is essentially smooth and uninterrupted so as to be more easily filled with cargo and more easily cleaned when necessary.

4. The improved lighter of claim 1 wherein said bottom, side walls and end walls are each formed with said compartmented double wall construction and with overall plan congurations of parallelograms having right angle corners, whereby the lighter has a at bottom with vertical side and end walls connected at right angles thereto so as to provide a maximum use of cargo space when a number of such lighters are stacked and aligned aboard a cargo ship.

5. The improved lighter of claim 4 wherein the top of the lighter includes a relatively large hatchway for receiving cargo within the lighter, and wherein there is no overhang of the upper edges of said side walls along the side margins of said hatchway.

6. The improved lighter of claim 5, and including a hatch cover assembly for closing the hatchway of the lighter.

7. The improved lighter of claim 6 wherein said hatch cover assembly can be folded to an open position, and

including a deck overhang from at least one end wall of the lighter for supporting the hatch cover when it is in a folded condition.

8. The improved lighter of claim 4, and including means attached to the corners of said lighter for lifting the same into and out of a body of water.

9. The improved lighter of claim 8 wherein said lifting means comprise reinforced corner posts included within the double wall construction of the lighter, said corner posts having upper and lower end configurations which mate with corner posts of lighters stacked relative to said improved lighter.

10. The improved lighter of claim 8 wherein said lifting means includes corner post constructions at the corners of said lighter for receiving spreader means between all of said corner posts when the lighter is to be lifted or lowered, whereby stresses in the hull of said lighter are more uniformly distributed.

11. An improved lighter construction suitable for hauling cargo between a port and a cargo ship and for being stowed or carried aboard the cargo ship in a stacked relationship to lighters of similar construction, comprising a hull having a bottom, side walls and end walls, all

of which are formed with a double wall construction so as to provide a1 reliable buoyancy for the lighter without a requirement for space-consuming reserve buoyancy tanks, said double wall construction also providing for increased strength of the lighter and greater safety for cargo by protecting the cargo on al] sides from damage resulting from a rupture of either wall making up the double wall construction, said double wall construction of the hull further comprising: I

an inner wall and an outer wall, said inner Wall being made up of a plurality of hull plate members connected in edge-to-edge relationships to form a continuous inner wall structure, and including divider plate members connected between the edges of adjoining hull plate members and extending at substantially right angles from the inner wall so as to be connected to said outer wall thereby forming a plurality of sealed compartments between said inner and outer walls, said hull plate members of at least one of said walls having flanges along their edges so that the anges can be connected to edges of divider plate members which are included between the flanges of adjoining hull plate members, said flanges functioning to support said divider plate members while a divider plate member is being welded between an adjoining pair of hull plate members.

12. The improved lighter of claim 11 wherein said hull plate members are welded in edge-to-edge relationships so as to include edges of said divider plate members therebetween.

13. The improved lighter of claim 12 wherein said outer wall comprises relatively large sheets of material having said divider plate members welded to inner surfaces of the large sheets.

14. The improved lighter of claim 11 wherein the top of the lighter includes a relatively large hatchway for receiving cargo within the lighter, amd wherein there is no overhang of the upper edges of said side walls along the side margins of said hatchway.

15. The improved lighter of claim 11, and including means attached to the corners of said lighter for lifting the same into and out of a body of walter.

16. The improved lighter of claim 15 wherein said lifting means comprise reinforced corner posts included within the double wall construction of the lighter, said corner posts having upper and lower end configurations which mate with corner posts of lighters stacked relative to said improved lighter.

References Cited UNITED STATES PATENTS 1,514,001 1l/l924 Koppe 114-26 1,764,585 6/1930 Taylor 114-26 X 3,045,631 7/ 1962 Stransky 114-201 3,361,274 1/1968 Goldman 114-72 X TRYGVE M. BLIX, Primary Examiner.

U.S. Cl. X.R. 

